public void Redraw()
{
Point[] points = new Point[4];
int r = (int)(endPoint.X - startPoint.X) / 2;
var center = new PointF(StartPoint.X + r, startPoint.Y + r);
points[0] = startPoint;
points[1] = new Point(startPoint.X + r, startPoint.Y);
points[2] = endPoint;
points[3] = new Point(endPoint.X - r - (int)(2 * r), endPoint.Y);
var brush = new SolidBrush(FillColor);
DrawPanel.DrawPolygon(DrPen, points);
DrawPanel.FillPolygon(brush, points);
brush.Dispose();
}